Rotary distributor for pressure cuff tourniquets



Jan. 25, 1965 H. J. RAND 3,167,067

ROTARY DISTRIBUTOR FOR PRESSURE CUFF TOURNIQUETS Filed July 24, 1962 IN VEN TOR.

Y HEN/Ry J" Ram/0 HTTO/YNEYS United States Patent 3,167,867 RQTARY DETREEUTQR FGR PRESSURE CUFF TOURNKQUETS Henry J. Rand, Cieveiand, Ohio, assignor to R. F. Scherer Corporation, Detroit, Mich, a corporation of Michigan Filed duty 24, 1 962, Ser. No. 211,976 1 Claim. (Ci. Hit-24) This invention relates to improvements in a rotary dis tributor for a plurality of pressure cuff tourniquets and to a fail-safe arrangement thereof.

While other uses of this invention are possible, one contemplated use thereof is in acute heart failure associated with pulmonary edema. In treating this condition, cutf tourniquets are often applied to the proximal parts of the arms and legs of the patent thus impeding the venous return to the heart. Unless the amount and time periods of application of pressure to the various limbs of the patient is carefully controlled, arterial occlusion may be produced, resulting in a loss of a limb, or deep vein thrombosis may be caused.

An object of the present invention is to provide an automatic rotary distributor where a plurality of pressure cuff tourniquets permitting precise controlled venous compres sion and minimizing the possibility of venous thrombosis, together with an arrangement of the valving mechanism whereby it the driving devices employed in the apparatus should fail in their function, all cuff tourniquets in the system will be deflated without danger to the patient.

Other objects and advantages of the present invention will be apparent from the accompanying description taken in connection with the drawings, and the essential features thereof will be set forth in the appended claim.

In the drawings,

FIG. 1 is a diagrammatic showing of the apparatus necessary for the carrying out of the present invention;

FIGS. 2, 3 and 4 are fragmental sectional views taken along similarly numbered lines in FIG. 1; while FIG. 5 is a transverse sectional view, enlarged, taken along the line 5-5 of FIG. 2.

Referring first to FIG. 1 of the drawings, four pressure cuff tourniquets are indicated at l, 2, 3 and 4 adapted for application to the proximal parts respectively of the four extremities of the arms and legs of the patient in the treatment of acute heart failure as outlined above. A suitable supply of air under pressure is provided for the inflation of the cuff tourniquets. In the present illustration, an air compressor is shown at It driven by an electric motor 11 which is supplied by current from the source L1, L2 upon proper actuation of the switch 12. Air from the compressor passes through the conduit 13, then through a reservoir 14, then through conduits 15, =16 and 17 to a distributor plate 18 which is fixed in position by any suitable means. Other connections in the air system include a conduit '19 located between reseiwoir '14 and distributor plate '18 and leading to a controlled outlet to the atmosphere through needle valve 2%, the position of which is adjustable 'by means of a control member 2-1. Another conduit connection in the air system between the reservoir 14 and the distributor plate 18 is through line 22 to a pressure gauge 23 upon which may be read the pressure applied to the cuff tourniquets as will appear.

For the orderly distribution of air under pressure from the distributor plate 18 to the various cuff tourniquets, a rotary air valve 24 is provided having a fiat face mating with the bottom of the distributor plate 13 in a manner about to be described. The valve 24 is fastened by cotter pin 25 to the driven shaft 26 of a gear reduction unit 27 which is driven by an electric motor 28 also energized from the source L1, L2 when energized by the switch 12. The shaft 26 passes freely through the fixed plate 18 and seals are provided where necessary to prevent leakage between the parts 18, 24, and 26.

The cooperation between the distributor plate 18 and the rotary valve 24 will now be described. The air inlet tube 17 enters the plate 18 radially thereof as seen in FIGS. 1, 2 and 3. Within plate 18 tube 17 communicates with a vertical passageway 17' which extends downwardly as shown in FIG. 5 to the interface between plate 18 and rotary valve 24. At this zone it communicates with a circular passageway 29 in the upper face of valve 24. This passage communicates through a radial passageway 39 with an arcuate air inlet groove 31 which in this embodiment extends through an arc of about 255. In other Words, the angle A indicated in FIG. 4 is approximately 105. The tubes 1a, 2a, 3a and 4a extending respectively to the cuif tourniquets -1, 2, 3 and 4, each enter the distributor plate 18 radially thereof and each communicates with a vertical passageway lb, 212, 3b and 4b, respectively, and each of these vertical passageways extends down to the interface between plate 18 and valve 24, terminating opposite the arcuate air groove 31. It will be noted that the passageways 1b, 2b, 3b and 4b are spaced evenly apart. There is an air exhaust opening 3-2 through valve 24 as shown in FIGS. 2 and 4 extending from the interface between 18 and 24 downwardly to the lower face of valve 24 where it discharges into the atmosphere. This opening 32 is arcuately in line with the air groove 31 and spaced from the trailing end of the groove 3-1 preferably by a distance slightly less than the diameter of the opening 32;. The openings 32, 1b, 2b, 3b and 4b are all approximately the size of the inside diameter of the tubing 1a, 2a, 3a and ta. The direction of rotation of the valve 24 when in use is indicated by the arrow B in FIGS. 2 and 4.

The operation of this device should now be apparent. The switch 12 is thrown to energize motors i l and 23. Motor It drives the air compressor l0 which fills the reservoir 14 and the supply system with air under pressure. Needle valve 2% is adjusted by member 21 so as to maintain the proper pressure in the air system and to carry out the functions about to be described. The motor 28 through gear reduction 27 drives the shaft 26 which rotates valve 24 in the direction of the arrow B of FIGS. 2 and 4. It will be noted that the air groove 31 covers all but one of the air outlet openings leading to the cuff tourniquets. In the position of the parts shown in the rawings, compressed air entering through line 17 and passageway 17' traverses the circular groove 29 and the radial groove 3! to air inlet groove 31. The air then passes through openings 1b, 2b and 4b to the proper conduits to energize the cuff tourniquets 1, 2 and 4 creating in them the desired pressure which usually is set between 35 and 50 millimeters of mercury although this can be arranged as desired. At this time, the cuff tourniquet 3 is completely deflated and this occurred when the discharge opening 32 rotated past the vertical passageway 3b. Continued rotation of valve 24 in the direction of the arrow B will cause the trailing end of arcua-te groove 31 (shown in dot-dash lines in FIG. 3) to pass beyond the opening 211 thus cutting off the air to the cuff tourniquet 2. Shortly thereafter, the exhaust opening 32 comes into registry with the opening 2b thus exhausting that cuff tourniquet. At the same time, the leading end of the arcuate groove 31 comes into registry with the opening 3b so as to pressurize the cuif tourniquet 3. This situation continues progressively with the arcuate groove 31 pressurizing three of the cuff tourniquets while the exhaust opening 32 discharges the pressurized air from one of the cuif tourniquets.

At the cross-over points where each cuff in turn is being decompressed, the air system is temporarily in communication with the exhaust opening 32 for a period generally between about 15 to 30 seconds and this occurs when the exhaust hole 32 is in communication with one of the cuff openings 15:, 2b, 3b or 4]) while this cuff opening Patented Jan. 26, 19b5 is at the same time in communication with the arcuate groove 31. This condition occurs because the exhaust hole 32 is less than one diameter (of holes 1b to 4b) from the trailing end of arcuate groove 31. At these very brief cross-over periods the variables are so adjusted that the pressure in the three pressurized cuff tourniquets drops to approximately /2 of the fully inflated pressure.

In one form of this apparatus, the rotary valve 24 makes one complete rotation every 44 or 45 minutes. This means that each of the cuff tourniquets is completely inflated, or substantially so, for three-quarters of this period or 33 to 33% minutes, and each of the cuffs is then completely deilated for A of the total period or approximately 11 or 11% minutes. This also means that during the approximately 33 minutes that each cuff tourniquet is inflated, there are two short periods of between 15 and 30 seconds each where the pressure drops to approximately half of'the fully inflated level. This permits venous compression and minimizes the occurrence of venous thrombosis by partial deflation of all of the cuffs approximately every 11 minutes.

If there should be a failure of electrical power, no harm can come to the patient because in the normal position of the parts, one cufi tourniquet is already deflated and the other three cuff tourniquets will be soon deflated through the needle valve 29. In one extreme position of the parts, all of the openings 1b, 2b, 3b and 4b are open to atmosphere either through the needle valve 20 or through the exhaust hole 32 of the rotary valve.

What is claimed is: In the combination of a plurality of pressure cuff tourniquets and a' rotary distributor for inflating said plurality of pressure cuff tourniquets and for progressively deflating each cuif tourniquet one at a time in a continuous cycle, the improvement in said distributor comprising a distributor plate having a plurality of air outlets with means for attachment one to each cufl, said outlets being of equal arcuate extent and evenly spaced arcuately about said plate, a rotary air valve having a face mating with said plate in a substantially air-tight manner, an arcuate air groove in said valve of a length to communicate at all times with all but one of said air outlets, a compressed air source and conduit system at all times communicating a/ with said arcuate air groove, means for continuously ro tating said valve in one direction at a constant rat-e'relative to said distributor plate, there being an airvexhaust opening in said valve communicating from said mating face to atmosphere only, said opening being arcuately in line With said air groove and spaced from the trailing end of said arcuate air groove as it rotates by an amount less than the arcuate extent of one of said air outlets to a cuff, there being an open bleeder valve of limited flow capacity communicating between said system and atmosphere between said source and said arcuate air groove, whereby each of said cuffs in turn is placed in communication with said exhaust opening for deflation and at such time the air groove is in communication briefly with atmosphere so as to temporarily reduce the pressure in all cuffs not in deflatable communication with the exhaust opening.

References Cited in the file of this patent UNITED STATES PATENTS 

